The present invention relates to a video camera unit and, more particularly, to a compact and blight video camera unit.
Recently, there has been developed a very compact 1/3-inch solid-state image pickup device, and efforts have been made to develop a door scope TV camera or the like as one of its main applications.
A wide angle lens used therein is constructed by combining 8 to 10 lenses since it must have certain optical properties relative to spherical aberration, astigmatism, distortion aberration, chromatic aberration, sine condition, etc. (as disclosed in e.g. Japanese Patent Unexamined Publication No. 48-64927). Further, a solid-state image pickup chip (IC chip) constructed by combining a photodiode and a switch MOSFET is publicly known as disclosed in e.g. Japanese Patent Unexamined Publication No. 56-152382. In the television camera for monitoring, family use, etc., which uses the above solid-state image pickup chip, an optical lens is provided with an automatic diaphragm or stop mechanism.
However, the above wide angle lens, which is constructed by many lenses, is not suitable to miniaturization.
Also, the above lens provided with an automatic diaphragm mechanism requires relatively complicated mechanical component parts, resulting in enlargement of the lens portion in the television camera and increase in production cost therefor. Further, the above automatic diaphragm mechanism which is constructed by relatively complicated mechanical component parts involves another problem in the point of reliability as well due to possible abrasion of the mechanical structure portion.